package 反转链表;

class ListNode {
    int val;
    ListNode next;
    ListNode() {}
    ListNode(int val) { this.val = val; }
    ListNode(int val,ListNode next) { this.val = val; this.next = next; }
}

class Solution {
    public ListNode reverseList(ListNode head) {
        if(head == null || head.next == null){
            return head;
        }
        
        ListNode newHead = reverseList(head.next);
        head.next.next = head;
        head.next = null;

        return newHead;
    }
}